Unsaturated organoalkoxysilanes containing an acryloyloxy group, such as 3-acryloyloxypropyltriethoxysilane, have been produced by the nucleophilic substitution reaction of a haloorganoalkoxysilane with a metal salt of an unsaturated carboxylic acid, such as sodium acrylate, in the presence of a suitable phase-transfer catalyst. In addition to the desired silane product, this process produces a metal halide precipitate as a by-product, which is unwanted in the silane product and must be removed.
A portion of the metal halide precipitate has a fine particle size that does not settle into a distinct layer making decanting the product from the precipitate difficult on a commercial scale. In addition, washing with water is not practiced to avoid hydrolysis of the silane and formation of dispersions that are hard to separate. Thus, the metal halide is typically removed by filtration. However, to filter the fine particle size and large amount of the metal halide precipitate requires significant time, so filtration is a significant bottleneck in commercial scale production.
Therefore, there is a need for a process for producing an acryloyloxysilane that produces a metal halide by-product precipitate that is more easily removed from the organoalkoxysilane containing an acryloyloxy group. There is also a need for a new process to quickly remove a metal halide from a mixture of an acryloyloxysilane and the metal halide.